Andean uplift, drainage basin formation, and the evolution of plants living in fast‐flowing aquatic ecosystems in northern South America

2021 ◽  
Author(s):  
Ana M. Bedoya ◽  
Adam D. Leaché ◽  
Richard G. Olmstead
Keyword(s):  
South America ◽  
Aquatic Ecosystems ◽  
Drainage Basin ◽  
Andean Uplift ◽  
Basin Formation ◽  
Northern South America

scholarly journals Andean uplift, drainage basin formation, and the evolution of riverweeds (Marathrum, Podostemaceae) in northern South America

2020 ◽  
Author(s):  
Ana M. Bedoya ◽  
Adam D. Leaché ◽  
Richard G. Olmstead
Keyword(s):  
South America ◽  
Landscape Change ◽  
Drainage Basin ◽  
Parental Line ◽  
List Type ◽  
Basin Formation ◽  
Northern South America ◽  
The Impact ◽  
River Drainages

SummaryNorthern South America is a geologically dynamic and species-rich region. While fossil and stratigraphic data show that reconfiguration of river drainages resulted from mountain uplift in the tropical Andes, investigations of the impact of landscape change on the evolution of the flora in the region have been restricted to terrestrial taxa.We explore the role of landscape change on the evolution of plants living strictly in rivers across drainage basins in northern South America by conducting population structure, phylogenomic, phylogenetic networks, and divergence-dating analyses for populations of riverweeds (Marathrum, Podostemaceae).We show that mountain uplift and drainage basin formation isolated populations of Marathrum and created barriers to gene flow across rivers drainages. Sympatric species hybridize and the hybrids show the phenotype of one parental line. We propose that the pattern of divergence of populations reflect the formation of river drainages, which was not complete until <4 MaOur study provides a clear picture of the role of landscape change in shaping the evolution of riverweeds in northern South America, advances our understanding of the reproductive biology of this remarkable group of plants, and spotlights the impact of hybridization in phylogenetic inference.

Megafan Environments in Northern South America and their Impact on Amazon Neogene Aquatic Ecosystems

2011 ◽  
pp. 162-184 ◽  
Author(s):  
M. Justin Wilkinson ◽  
Larry G. Marshall ◽  
John G. Lundberg ◽  
Mikhail H. Kreslavsky
Keyword(s):  
South America ◽  
Aquatic Ecosystems ◽  
Northern South America

scholarly journals Gene flow and Andean uplift shape the diversification ofGasteracantha cancriformis(Araneae: Araneidae) in Northern South America

2018 ◽  
Vol 8 (14) ◽  
pp. 7131-7142 ◽  
Author(s):  
Fabian C. Salgado-Roa ◽  
Carolina Pardo-Diaz ◽  
Eloisa Lasso ◽  
Carlos F. Arias ◽  
Vera Nisaka Solferini ◽  
...  
Keyword(s):  
Gene Flow ◽  
South America ◽  
Andean Uplift ◽  
Northern South America

scholarly journals Gene flow and Andean uplift shape the diversification of Gasteracantha cancriformis (Araneae: Araneidae) in Northern South America

2018 ◽  
Author(s):  
Fabian C. Salgado-Roa ◽  
Carolina Pardo-Diaz ◽  
Eloisa Lasso De Paulis ◽  
Carlos F. Arias ◽  
Vera Nisaka Solferini ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
South America ◽  
Color Polymorphism ◽  
Early Pleistocene ◽  
Eastern Cordillera ◽  
Colombian Andes ◽  
The Face ◽  
Andean Uplift ◽  
Northern South America

ABSTRACTAimThe Andean uplift has played a major role shaping the current Neotropical biodiversity. However, in arthropods other than butterflies, little is known about how this geographic barrier has impacted species historical diversification. Here we examined the phylogeography of the widespread and color polymorphic spider Gasteracantha cancriformis to: (i) evaluate the effect of the northern Andean uplift on its divergence and, (ii) assess whether its diversification occurred in the presence of gene flow.LocationNorthern Andes and BrazilMethodsWe inferred phylogenetic relationships and divergence times in G. cancriformis using mitochondrial and nuclear data from 105 individuals in northern South America. Genetic diversity, divergence and population structure were quantified. We also compared multiple demographic scenarios for this species using a model-based approach (PHRAPL) to establish divergence with or without gene flow. Finally, we evaluated the association between genetic variation and color polymorphism.ResultsBoth nuclear and mitochondrial data supported two well-differentiated clades, which correspond to populations occurring in opposite sides of the Eastern cordillera of the Colombian Andes. The splitting between these clades occurred in the early Pleistocene, around 2.13 million years ago (95% HPD = 0.98–3.93).Despite this vicariant event, there is shared genetic variation between the clades, which is better explained by a scenario of historical divergence in the face of gene flow. Color polymorphism was randomly scattered in both clades and is not statistically associated with the genetic variation studied here.Main ConclusionsThe final uplift of Eastern cordillera of the Colombian Andes was identified as the major force that shaped the diversification of G. cancriformis in Northern South America, resulting in a cis- and trans-Andean phylogeographic structure for the species. The divergence in the face of gene flow between cis- and trans-Andean populations found for this spider has been likely facilitated by the presence of low-elevation passes across the Eastern Colombian cordillera. Our work constitutes the first example where the Andean uplift coupled with gene flow influenced the evolutionary history of an arachnid lineage.

scholarly journals The changing course of the Amazon River in the Neogene: center stage for Neotropical diversification

2018 ◽  
Vol 16 (3) ◽  
Author(s):  
James S. Albert ◽  
Pedro Val ◽  
Carina Hoorn
Keyword(s):  
South America ◽  
Drainage Basin ◽  
Sedimentary Basins ◽  
Coarse Grained ◽  
Amazon River ◽  
Geological Evidence ◽  
Continental Scale ◽  
River Capture ◽  
Northern South America ◽  
Seasonally Flooded

ABSTRACT We review geological evidence on the origin of the modern transcontinental Amazon River, and the paleogeographic history of riverine connections among the principal sedimentary basins of northern South America through the Neogene. Data are reviewed from new geochronological datasets using radiogenic and stable isotopes, and from traditional geochronological methods, including sedimentology, structural mapping, sonic and seismic logging, and biostratigraphy. The modern Amazon River and the continental-scale Amazon drainage basin were assembled during the late Miocene and Pliocene, via some of the largest purported river capture events in Earth history. Andean sediments are first recorded in the Amazon Fan at about 10.1-9.4 Ma, with a large increase in sedimentation at about 4.5 Ma. The transcontinental Amazon River therefore formed over a period of about 4.9-5.6 million years, by means of several river capture events. The origins of the modern Amazon River are hypothesized to be linked with that of mega-wetland landscapes of tropical South America (e.g. várzeas, pantanals, seasonally flooded savannahs). Mega-wetlands have persisted over about 10% northern South America under different configurations for >15 million years. Although the paleogeographic reconstructions presented are simplistic and coarse-grained, they are offered to inspire the collection and analysis of new sedimentological and geochronological datasets.

scholarly journals Air quality variations in Northern South America during the COVID-19 lockdown

2020 ◽  
Vol 749 ◽  
pp. 141621 ◽  
Author(s):  
Juan F. Mendez-Espinosa ◽  
Nestor Y. Rojas ◽  
Jorge Vargas ◽  
Jorge E. Pachón ◽  
Luis C. Belalcazar ◽  
...  
Keyword(s):  
Air Quality ◽  
South America ◽  
Northern South America

Ground-motion model for subduction earthquakes in northern South America

2021 ◽  
pp. 875529302110275
Author(s):  
Carlos A Arteta ◽  
Cesar A Pajaro ◽  
Vicente Mercado ◽  
Julián Montejo ◽  
Mónica Arcila ◽  
...  
Keyword(s):  
South America ◽  
Ground Motion ◽  
Ground Motions ◽  
Strong Motion ◽  
Motion Prediction ◽  
Depth Range ◽  
Ground Motion Prediction ◽  
Natural Period ◽  
Nazca Plate ◽  
Northern South America

Subduction ground motions in northern South America are about a factor of 2 smaller than the ground motions for similar events in other regions. Nevertheless, historical and recent large-interface and intermediate-depth slab earthquakes of moment magnitudes Mw = 7.8 (Ecuador, 2016) and 7.2 (Colombia, 2012) evidenced the vast potential damage that vulnerable populations close to earthquake epicenters could experience. This article proposes a new empirical ground-motion prediction model for subduction events in northern South America, a regionalization of the global AG2020 ground-motion prediction equations. An updated ground-motion database curated by the Colombian Geological Survey is employed. It comprises recordings from earthquakes associated with the subduction of the Nazca plate gathered by the National Strong Motion Network in Colombia and by the Institute of Geophysics at Escuela Politécnica Nacional in Ecuador. The regional terms of our model are estimated with 539 records from 60 subduction events in Colombia and Ecuador with epicenters in the range of −0.6° to 7.6°N and 75.5° to 79.6°W, with Mw≥4.5, hypocentral depth range of 4 ≤  Zhypo ≤ 210 km, for distances up to 350 km. The model includes forearc and backarc terms to account for larger attenuation at backarc sites for slab events and site categorization based on natural period. The proposed model corrects the median AG2020 global model to better account for the larger attenuation of local ground motions and includes a partially non-ergodic variance model.

STUDIES ON STRONGYLOIDES AGOUTII SP. NOV. FROM THE AGOUTI (DASYPROCTA AGOUTI)

1940 ◽  
Vol 18d (5) ◽  
pp. 173-190 ◽  
Author(s):  
Henry J. Griffiths
Keyword(s):  
Seasonal Variation ◽  
South America ◽  
Biological Study ◽  
Free Living ◽  
Classical Studies ◽  
Group A ◽  
Northern South America

A morphological and biological study is presented of a hitherto unrecorded member of the genus Strongyloides from the golden-rumped agouti (Dasyprocta agouti), a rodent native to Trinidad, B.W.I., and northern South America. The name Strongyloides agoutii sp. nov. is proposed for this species.Observations on the free-living development over a period of three years showed the indirect type to prevail; no seasonal variation was observed. Continuous propagation of the free-living generation of this species was not observed in faecal cultures or on artificial media.A brief résumé of the classical studies on species of the genus Strongyloides is included, together with a summary of existing hypotheses and theories on the biology of this group. A list of species and hosts for this genus is given.

Observed warming over northern South America has an anthropogenic origin

2017 ◽  
Vol 51 (5-6) ◽  
pp. 1901-1914 ◽  
Author(s):  
Armineh Barkhordarian ◽  
Hans von Storch ◽  
Eduardo Zorita ◽  
Paul C. Loikith ◽  
Carlos R. Mechoso
Keyword(s):  
South America ◽  
Anthropogenic Origin ◽  
Northern South America
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